I was hoping it would be a few hundred worth of parts... Clearly that was a massive dream.
In the end I went with a MY09 VR model anyway!
Now I just need to decide what to do next, will have to start off with small upgrades after my wallet is still hurting from the purchase... K&N+ECU Tune? New head unit (MMCS?) and bluetooth / parking sensors? Any other small upgrades I should consider?
Thanks again!
EDIT: I should add my thoughts to anyone else thinking the same as me...
Auto headlights - Is kinda cool. I find the main benefit of it is to turn lights off automatically when I park. I don't get that annoying 'beeeeeeep' telling me to turn them off. As for coming on automatically... It does a good job of this, coming on less than 10 seconds after I thought to myself it was getting dark and wondering when the lights would come on.
It was still bright, street lamps weren't even on yet... But I was quite happy with the timing. Over all, if you had an ES, this is probably only worth a 2.5 out of 5 on the 'how badly you should upgrade it' chart

Auto washers - Not worth it... To be fair, I've only driven ~ 2,000km from Adelaide to Geelong (Via Canberra... Don't ask) and haven't had actual rain yet. Although it did decide to turn on and smear dead locust all over my windscreen. My guess it mistook locust guts for rain, and turning on really wasn't appreciated as I had to pull over and manually clear a hole in the windscreen to see out of. I'm giving this one 1/5. I can't see myself using it, although may revist it after I have had an actual legitimate need to use it (I have just washed my car today... So expect it to rain shortly

6 disc MP3 head unit - Life saver. Seriously. You can easily fit 2,000KMs worth of MP3s onto 6 CDs. Select your favourite albums, burn to CD and just enjoy it like a radio station that only plays songs you like.
Although it is an OEM head unit... If you don't have it already, you could probably get similar results from a brand name. My only complaint is the simplistic display and the fact that it doesnt have a USB input on the face... I am considering adding on an iPod cable to reduce the need to burn CDs all the time. Giving this one 3/5 ... Which is lower than what its worth, but if you don't have it, there are much better, cheaper options available out there. If you do have it... Its a very good OEM unit
Steering wheel controls - Again, another feature I loved... And got used quite alot with all of my music. Its something so simple, and maybe the lazy side of me doesnt like reaching the extra 30cms for the head unit controls... But I'm giving this a 4/5 rating
Body kit, spolier, alloy wheels etc. - This will be a personal thing you can get by just looking at the thing... But I think it makes a huge difference to the appearance of the car and makes it stand out a bit from all of the fleet ES cars out there. Again, there are third-party items you can install instead of the OEM version though. 4/5
Extra airbags - This was the deal breaker for me. Looking at used Lancers, there is only a few grand difference between the ES and VR, and on the airbags alone, it is worth the upgrade. 5/5 especially as I think it is near on impossible to upgrade yourself.